if 5>12:
    print(" 5 is greater than 12 ")
    print(" 22222")
else:
    print("5 is less than 2")

age=30;
if age<18:
    print("you are underaged")
    # && 不可用
elif age>=18 & age<30:
    print("you are young")
elif age>=30 & age<50:
    print("you are middle-aged")
else :
    print("you are old")

year = input("enter your year")
if(year%4==0 and year%100!=0) or (year%400==0):
    print("%d闰年"%year)
else:
     print("%d不是闰年"%year)

a=int(input("请输入a"))
# ctrl+d 复制一行
# ctrl + alt + L 格式化代码
b=int(input("请输入b"))
c=int(input("请输入c"))
if a>b:
    if a>c:
        print("a is the greatest number")
    else:
        print("c is the greatest number")
else:
  if b>c:
    print("b is the greatest number")
  else:
      print("c is the greatest number")


num1=float(input("请输入第一个数"))
num2=float(input("请输入第二个数"))
op=input("请输入运算符")
if op=="+":
    print(num1+num2)
elif op=="-":
    print(num1-num2)
elif op=="*":
    print(num1*num2)
elif op=="/":
    print(num1/num2)
else:
    print("输入错误")